[V2.0] Add api parsing

[cbangera2]

closes #3

[Copilot]

Pull request overview

This PR represents a major version 2.0 release that fundamentally rewrites the Credit Karma transaction extraction mechanism from DOM-based scrolling to GraphQL API-based fetching, resulting in significantly faster performance and deeper historical data access.

Key changes:

• Implemented GraphQL API-based extraction with automatic fallback to scroll-based method
• Redesigned UI with modern card-based layout, dark mode support, and column selection
• Added two-phase data fetching strategy (recent + historical) to handle API pagination limits

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 26 comments.

Show a summary per file

File	Description
content.js	Added 650+ lines of API extraction logic including authentication, GraphQL queries, token management, pagination, and enhanced CSV generation with column filtering
popup.js	Refactored export logic to support API toggle, column preferences, quick date selection, and improved error handling
popup.html	Complete UI redesign with card-based sections for settings, file types, and column selection; moved CSS to external file
popup.css	New CSS file with comprehensive theming system using CSS variables for light/dark modes and modern styling
manifest.json	Version bump to 2.0 with formatting improvements
README.md	Updated documentation to highlight v2.0 API features and simplified installation instructions

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